Thermal management using endothermic heat sink

A thermal management system includes a slurry generator, an injector pump coupled to the slurry generator, a heat exchanger reactor coupled to the injector pump, wherein the heat exchanger reactor is adapted to subject a thermally expendable heat absorption material to a temperature above 60° C. and a pressure below 3 kPa, and wherein the expendable heat absorption material endothermically decomposes into a gaseous by-product. A vapor cycle system is coupled to the heat exchanger reactor and is operatively connected to a thermal load. A thermal energy storage system may be coupled to the vapor cycle system and the thermal load. The thermal energy storage system may isolate the heat exchanger reactor from thermal load transients of the thermal load.